The invention is a gas bag arrangement for a motor vehicle safety system comprising a gas generator and an airbag connected thereto that unfolds and becomes inflated by the gas produced by the gas generator when triggered, two partial gas flows exiting from the gas generator and acting separately upon the material of the airbag.
DE 21 50 744 C3 describes a gas bag arrangement with the aforesaid features; the gas generator described therein is set to generate at staggered intervals of time two partial gas flows, of which a first smaller partial gas flow initially pushes the airbag out of a container, while the partial gas flow released later in time inflates the airbag completely. Although such an embodiment reduces the risk of damage to the material of the airbag caused by a gas flow striking the material of the airbag at high pressure during the initial stage, pressure peaks still have a negative effect, especially in association with igniting the portion of fuel used to produce the quantity of gas for inflating the airbag.
The object of the invention is therefore to improve the protection of the material of the airbag from the gas flow striking it in a gas bag arrangement of the aforesaid type.
This object is achieved, including advantageous embodiments and further embodiments of the invention, using the contents of the claims following this specification.
Essentially the invention provides a housing that conducts the gas produced towards a gas discharge area, the gas discharge area of the housing constituting two partial discharge areas forming a single direction of discharge flow for the gas produced and arranged in staggered positions in the direction of gas discharged from said housing in relation to the connected airbag.
The advantage of the invention is that when the gas is produced, pressure peaks that occur due to baffling and dividing the gas flow produced in the housing are eliminated so that associated stress on the material of the airbag is reduced in that region of the airbag that connects to the gas discharge area of the housing. The staggered positions of the two points of discharge of the divided gas flow in the connected airbag lead to further protection of the material of the airbag. That is, the air located in the retention chamber is forced through the openings of the gas discharge area by the gas flow released at high speed and thus constitutes a cushion of air for the unfolding of the airbag.
The invention can be used particularly advantageously on gas bag arrangements in which the gas generator in the motor vehicle is arranged relative to physically separated airbags such that the gas flow, e.g., is conducted via a tubular connector to the airbag to be inflated, as described, e.g., in DE 296 05 896 U1 or GB 2 297 950 A for various applications. In this case, the connector tube is stressed in a particular manner, and this stressing of the connecting tube, which is also folded when at rest, is reduced in a particular manner in the invention.
In accordance with one exemplary embodiment of the invention it is provided that a first partial discharge area comprises a central discharge part that projects out of the gas conducting container and that extends into the airbag to be unfolded, and the second partial discharge area constitutes openings that are arranged in a circle surrounding the neck of the discharge part and that are situated in the wall of the housing. When the gas impacts, the air located in the retention chamber initially flows through the openings of the second partial discharge area and constitutes a cushion of air along the projecting discharge part. Not only does this cushion of air protect the unfolding of the connected regions of the folded material of the airbag, it also surrounds the partial gas flow flowing out of the discharge part and attenuates its direct contact with the material of the airbag.
Assuming symmetrical embodiment of the gas discharge area with the two partial discharge areas in the exemplary embodiment described in the foregoing, in accordance with an exemplary embodiment of the invention an arrangement can also be created in which the two partial discharge areas are arranged adjacent to each other within the walls of the housing in that a first partial discharge area comprises a discharge part that projects out of the housing in an asymmetrical arrangement and extends into the airbag to be unfolded and the second partial discharge area comprises openings arranged in the associated wall of the housing.
Using an application of the gas bag in accordance with DE 296 05 0896 U1 or GB 2 297 950 A, in one exemplary embodiment of the invention it is provided that the housing is tubular in shape and the gas discharge area is arranged at one end of the housing.
In accordance with one exemplary embodiment of the invention, the gas bag is drawn over the end of the tubular housing and fixed on the exterior of the housing.
In a first embodiment form of the invention it is provided that a separate gas generator for producing gas is arranged in the housing and that a retention chamber is formed in the interior of the housing between the gas generator and the gas discharge area. The advantage thereof is that pressure peaks produced when the gas generator is triggered are additionally reduced by means of additional deflection and also by the formation of the retention chamber in front of the gas discharge area.
In accordance with one exemplary embodiment of the invention, the occurrence of pressure peaks is further diminished in that the gas generator is provided with radial exit openings at its end that faces away from the discharge area, so that the gas the gas generator releases in the radial direction into the gas conducting container is deflected in an axial direction of flow before it discharges further through the gas discharge area of the gas conducting container.
In an additional exemplary embodiment of the invention it is provided that a gas-producing material is arranged directly in a section of the housing, wherein a retaining disk separates the gas-producing material and the gas discharge area from a retention chamber located in front of the gas discharge area. In accordance with other exemplary embodiments of the invention, this retaining disk can either merely fix the gas-producing material in the housing or can also comprise a burst function.
In addition, it can be provided that the housing comprises at its gas discharge area a baffle, or throttling, disk that faces the retention chamber, by means of which baffle disk pressure peaks that occur when the gas begins to discharge out of the housing can be additionally baffled (i.e., throttled).